作者:Ta-shue Chou、Ruei-Chih Chang
DOI:10.3987/com-93-6535
日期:——
N-Toluenesulfonyl- and N-(anilinocarbonyl)pyrazolo-3-sulfolenes have been prepared from the protected oxotetrahydrothiophenecarbaldehyde (7) via a sequence of hydrazone formation, ketal hydrolysis, cyclization, dehydration, and oxidation reactions. These N-substituents migrate between the two nitrogen atoms of the pyrazole ring at different stages. Extrusion of SO2 from N-anilinocarbonylpyrazolo-3-sulfolenes was achieved at 180-200 degrees C and the transient intermediate, the pyrazolo-o-quniodimethane, could be trapped with dienophiles.